1. Most of the exam is based on multiple-choice questions, but there can be a small number of questions that follow a different pattern. Microsoft reserves the right to change the question types at any time. But no, there are not 100 questions, the number
is significantly smaller. It varies from exam to exam, and once again Microsoft can change it at any time, but you can expect somewhere between 45 and 70 questions.
2. The passing score is 700 out of 1000. But it is not necessarily a percentage; the questions are graded on a (non-publicized) scale, so the actual number of questions that you need to get right could be more or could be less than 70%.
3. Yes, this is a good book. If you have studied the book and you also have a reasonable amount of experience writing ASP.NET applications, then you should be able to pass the exam without problems.
As to other resources, make sure that you have gone over the "Skills Measured" list in the exam description page, and verify that you have knowledge on each of the subjects mentioned there.
https://www.microsoft.com/learning/en-us/exam-70-515.aspx
